External Oscillator-less TDC based All-digital Temperature Sensor

Abstract

This paper presents a TDC based all-digital temperature sensor with small inaccuracy even at wide temperature range. The proposed sensor utilized CMOS inverters show different temperature characteristics to embed an oscillator that previous sensors have used as external component. Moreover, the temperature characteristic of a diode is used to improve the temperature inaccuracy. The sensor in 180nm CMOS process tested from -40°C to 200°C shows -2.56∼+2.84°C inaccuracy.